Bolt anchor



June 11, 1935 n H. w. PLElsTER r-:rAL 2,004,480

BOLT ANCHOR Filed oct. 9, 1954 5 Sheets-sheet' 1 ATTORNEY .Y

June 11, 1935. H. w. PLElsTER ET AL 2,004,480

BOLT ANCHOR Filed Oct. 9, 1934 3 Sheets-Sheet 2 E e a@ mm aan Eg Z T/,wFf, i L y Z; g

TORNEY June 11, 1935.' H, W, PLElSTER ET AL l 2,004,480

BOLT ANCHO Filed Oct. 9, 1934 3 Sheets-Sheet 3 ATTORNEY www PatentedJune11, 1935 ."C'orpbration, Garyyqoa, J a, stipulation; of?

' f Our invention''relatestoboltfanchors.

Our invention' further relates tosuch av bolt` anchor in whichthexnaxmum gripf'orbond willl be towards the endof the hole-removed`from I thesuriace ofc the support, `to prevent chippingor mai'ringofthe surface of the yvvall' or othersup-AV Our invention* moreparticularly `relates `to a bolt anchorhavinga shield formed ofalplurality of shield'memberahaving cooperating ini n clined'surfacesadapted tolslide longitudinally i upongeachcother in "situ, to obtain;fora given size boltI anchor shield,` `the `maximtun` grip or` theWallsfof a `hole ing Whichfitmisbond i With mounted. n

Our invention "comprises suchV a'holtlanchor which can be successfullyoperatedtwithout re gard" to the exactlength'of' a1screw,`` or other:expanding member,` n to be `used with a particular; length ofshieldrnembe'rs; vandwithoutregard i formed of. a pluralityof parts; inwhich one of shield member is provided `WithA asmoothext'erior surface,to permit its movementin situ.

area(y of lengagemerit` between the shield and the lag, or other "screw,with Vthe shield, na'nd`prevents*v strippingof the cooperating *meanscarriedby the n i shield, which means 'arejusuallyfemale threads'forinyprle oftheshiem members f 'i vided with weakening means` such,asi-af" groove orfslot, orsimila'rfmeans, `topermit;more readyj;compression 'of one or more ,of the shield mem# L 45` bers as the shieldis drivenlinto la hole, thereby]` eliminating, `or "lesse'ningfi' anychipping7` orV wall as thejshieldis ydriven horned'"vv j jj' Y Y v A i n`Our^inventionfurther covers arcuate bearing 50A :a surfaces betweentliemembers of the shield to i marring of the surface lofthemasonryforlother insure that'the greatest expansionoccurs ati-the"lkiniierrfend of the hole removedfromthe surfaceof thevvall so as to stillfurther prevent chipping" ormarringfof theivvall adjacentthe hole.`

i the lparts*is.provided Withmeans to anchorjor* resist movementy 'in'ahole;Whileitsicooperating i l expanding member which is usuallya lag orother screw.4 `This lincreases the hold for grip of the i i i i i i i-Fig. 16 is a l,cross"sectionfon line l6-I6 ofFig.` Our invention ifurther covers a shield member formed of some l. frigid metal, `such asImalleable iron, cast in an'ordinary sandlmold without the use of "alcore;';and,then, subsequently compress-2 n ing or distorting the shield,as: in `driving it into a holegsso that its mutilatedfemalev threadswill5 more closel'y'partially surround .the male thread i i l on the lagscrew,wor other expandingi'nember, g therebyopreventing the femalethreads; carried]V by the shield,f-fron1 being `stripped 'whenanexce'ssiveload is placed upon thebolt anchori l i 1o`Olminventionfurther relates to certaincomhina-tions,fsubeoinlzuinations,v articles of manu# factureandidetails'of construction, all of 'which l l willbemor'e fullyhereinafter ^described and pointedrout in theclaims.: l .i y Inthelrngures- Weihave showndiierent embodimentsofour inventiomthe same`reference numerals refer Ito" similar parts .in the several figureszz`y i gvFigL 1 is a side elevation ofjour bolt anchor L20 "shield'formedof two shield` members `I andZ 4 n fv showninpjuxtaposition.` Ourinvention A'further'fcovers `such* a shield *FigAis alverticalsectinonline 4-11 ofFig. 2. `25

1 Fig.` 5 is `an end View of-Fig.l2. i t 4 Fig.16 isia bottomplanvewofthe shield 'sec` 4 Quanta@ 1f A i i "Ou'r'invention `further covers suchal shield prof'l1 3Q f .vided with means to compressthefshield, when;iti's'iforced ordriven into a holehaving a diamef terfgsomewhat lessithan the greatest or overallf dianrieterA of vthe" bolt anchor, toyinsure `greater Fig. 101s a reversed planview of `the shield iuus-` `35i 1 1'ig912` is a side elevation of our bolt anchoriv `driven into ahole of slightly less diameterithan 4 n s the maximumproverall diameterofthe shield,"` Our invention further covers such ai shieldpro-- ishowing the'shield compressed or distorted byl `Fig\,"13 is, a sidemex/ation similar@lr'igiat showing the lag screw' screwed home toexpand? n thelbolt anchorand showing the Work Asecured-to theface of the'vvall.`

'Fig. 141s a longitudinal vertical section through Fi`gr15 is a crosssection, onanenlarged'scale,` n on jline I j-"I 5 yof 9 vbefore theshield isdrivenl i into Ta hole.` i

13, showing the compressionor distortion of the bers 29| and 2il2 areeach provided with weakening slots.

Fig. 20 is a cross section on line 2li-.f2.6 `of Fig. 19.

Fig. 2l is a fragmentary "view of a still another f modification inwhich the slidable shield member Billis provided with an inclined orwedge-shape thickened end, so that it, together with its complementaryfixed shield member, (not shown) will have a greater overall diameterthan that of the hole in which it is to be mounted.

Fig. 22.is a view similarto Fig. vZl'after the moveable shield member isdistorted or compressed by driving the shield member 36|, to.

gether with its complementary fixed vshield mem-Y ber (not shown)intof'a hole of less diameter than the overall diameter'of. said'twoshield members.V

Gur shield is ordinarily meant to be used in Aholes drilled, or.otherwise formed, in masonry,

brick, terra cotta, concrete or similar hard material. While it isadapted to be used in holes into which it i'its freely, `so that nohammering or forcing of the shield. is required to drive it home intothe hole, it is meant primarily to be used in holes which haveldiameters slightly less than the overall diameter of the shield.

By our invention we cheapen the cost of manufacture in that the 'shieldmembers can both be cast in ordinary sand molds without a core, and

are then, subsequently, by hand, or preferably 2' simply by driving theminto a hole of less dian1- eter than their overall diameter, caused-tobe distorted or compressed, so that aportionv of the shield members arecaused to change their shape. In the example shown, shield 2 iscompressed to a smaller diameter and, through the Vship lap, will, inturn, compress the slidable shield member I. 'When the slidable shieldmember I is compressed, more or less, its mutilated female threads willmore closely encircle the male threads of the llag, or other screw,thereby increasing the area of the mutilated female threads in Contactywith.

the male threads of thelag screw, so that a maximum load, for a givensize bolt'anchor, may be supported without fear of stripping thekfernale threads in the moveable shield member.

This also permits a smaller hole to be drilled in the support, whichreduces the cost of inl stallation.

VOther advantages will vbe apparent to those skilled in the art from thedetailed Adescription of the formsfof our invention illustrated, by wayof example, but to which our invention is not to be limited except asdened by our claims. f

In the preferred form of our invention our bolt,

anchor shield is formed, preferably, of two mem. bers I and 2. Theformer is a movable shield member andk lthe latter is axed shieldmember,y

in that after being once placed or forced into a hole 3 in a wall 4,Ithe member 2 is held rigid situ by any suitable means, as by its ribs5, 5

biting into the side of the hole 3. v.

The slidable shield member I is providedwith an open bottom B, Fig. 5,an arched or semi-cir cular top l' and` parallel `sides 88 and withfemale threads 9 and. preferablyvthough not necessarily, with weakeningmeans, such as a groove Ill, all cast at the same time in a sand moldwithout the aid of a core.

The sides 3, 8 with their mutilated female screw threads 9 are castparallel because if they were cast as a circular continuation of thesemi-circular top l, it would be impossible to withdraw the pattern fromthe sand withoutruining the mold.

It would accordingly be necessary to provide the -pattern with a coreprint in which latter an expensive core made of baked sand and molassesor similar `plastic cementitious mixture be placed individually in eachimpression in the sand to form the interior female threads. This wouldrequire a core` being made for each individual casting, which core wouldbe destroyed when the hard casting was later removed from the sand andgreatly multiply the cost of thecasting.

To'insure sale of such articles it is necessary that they be of themaximum strength for any given size bolt anchor, and, in addition, thattheir merchandizing be at such a low figure that they can beeconomically sold and used. Y

This slidable shield member I is also provided with an inclined wedgesurface I I, preferably arcuate, as shown at l2, Figs. 12 and 13, forapurpose to be more fully hereinafter described.-

It is also preferably provided with one portion I3 of a ship lap guide.This portion I3 has an inclined surface I4, Fig. l2, to cooperate withthe complementary portion I5 of the ship Vlap guide'.A

Thisportion I5 4is mounted on the fixed shield member 2, see Figs. 1, 7,9, 12 and 13. i

The shield member I is also provided with two shallow grooves I6, I6having slightlyinclined surfaces I'I, Ilfto receive bendable fasteninglugs I8,

'lhercomplementary*fixed shield member 2 is provided with transverseribs 5. 5 to hold it fast in situ. It is also providedwith guide lugs23, 23 to cooperate with a tongue I9, if suchtongue be used.

and also with head lugs 24, 24 which form a head v for vthe completebolt anchor shield. The axial bore of the rnembersI and 2is untapered.The

axial bore of lthe shield member 2 is unthreaded.k

Our shield is provided with compression means to compress or distort theparallel sides 8, r8 of the shield members-I Lwith its female threads 9.from the cast position, Figs. 5 and l5, to the-position shown in Fig. 16where the former parallel sides 8, 8 with their mutilated female threads9, aremade to vencircle,.more or less, the male thread of the lag 0rother screw 2 I, thereby` in. suring greater contact area ybetween themuti-. lated female threads 9 of the slidable shield member I andthemale threads of the lag screw When an excessive load is put upon thevshield through the lag or other screw, the increasedengaging areabetween the male threads and the mutilated female ,threaded willprevent' stripping of the.. latter and insures safety of the work 22. sl

Various forms of compression means maybe employed. In the drawingsshown, by wayof examplathe compression means, in the preferredconstruction, consist of compression members I5,

thereof, tothe details of which we do not de' sire to be limited, whichis claimed as new andv threads of an expanding screw to prevent failureof the bolt anchor under an excessive load. 2. The combination or" abolt anchor shield formed of two slidable shield members, a ship lapconnecting the members, an inclined surface between the members, andmeans to cause one of said shield members to slide upon the other.

3. The combination of a bolt anchor shield formed of two slidable shieldmembers, a ship lap connecting the members, inclined surfaces betweenthe members, means to cause one of said shield members to slide upon theother, and weakeningrmeans to permit the shield to be com- Y pressed ordistorted.

4, In a bolt anchor vprovided with means to engage with an expandingmember the anchor carrying means to increase the area of engagementbetween said rst means and the expand-v ing member to prevent failure ofthe bolt anchor when an excessive load is placed upon it.

5. In a bolt anchor provi-ded with means to engage with an expandingmember, the anchor carrying means vadapted to automatically increase thearea of engagement between sai-d iirst means and tie expanding member asthe bolt anchor isdriven into a hole in which it is tobe expanded, toprevent failure of the bolt anchor when an excessive load is placeduponit.

6. The combination in a bolt anchor of an ex*- panding member providedwith male threads and a shield provided with mutilated female threads,the shield carrying ymeans to increase the area of engagement betweenthe female threads of the shield and the male threads of the expandingmember. v

7. Thek combination in a bolt anchor of an expanding member providedwith male threads and a shield provided with mutilated female threads,the shield carryingfineans to automatically increase the area'ofengagement between the Vfemale threads oi the shield and the malethreads of the expanding member when the shield is driven into a hole inwhich it is to be expanded,

to preventstripping when` an' excessive loadis thrown upon the boltanchor. Y

8. In a bolt anchor provided with means to engage with an expandingmember the anchor being provided with integral means to increase thearea of engagement between said rst means and the expanding member toprevent failure of the bolt anchor when an excessive load is placed uponit. Y

9. In abolt-anchor formed of a plurality'oi longitudinally slidableparts, two of the slidable parts having open sides, one of the opensides being substantially U-shape in cross-section and havingsubstantially parallel sides, and means carried by the bolt anchor tocause said substantially parallel sides to assume a more or lesscircular contour when the bolt anchor is driven into a hole.

. 10. In a bolt anchor formed of a plurality of longitudinally slidableparts, two of the slidable parts having open sides, the interior of oneoi the slidable parts being unthreaded and the interior of the otherslidable part being provided with female threads and being formedsubstantially U-shape in cross-section with substantially parallelsides, and means carried by the bolt anchor to cause said substantiallyparallel sides to assume a more or less circular contour when the boltanchor isdriven into a hole, thereby permitting a greater area of itsfemale threads to engage with a lag or other expanding screw, to preventstripping when an excessive load is thrown on the bolt anchor.

1l.. In av bolt anchor formed of a plurality of longitudinally slidableparts, two of the slidable parts having open sides, one of the opensides being substantially U-shape in cross-section and havingsubstantially parallel sides, and integral means carried by the boltanchor to cause said substantially parallel sides to assume a more orless circular contour when the bolt anchor is driven into a hole.

' 12. In a bolt anchor formed of a plurality of longitudinally slidableparts, two of the slidable parts having open sides, the interior of onevof the slidable parts being unthreaded and the interior of the otherslidable part being provided with female threads and being formedsubstantially U-shape in cross-section with substantially parallelsides, and integral means carried by the bolt anchor to cause saidsubstantially parallel sides to assume a more or less circular contourwhen the bolt anchor is driven into a hole, thereby permitting a greaterarea of its female threads to engage with a lag or other expandingscrew, to prevent stripping when an excessive load is thrown on the boltanchor.

HENRY W. PLEISTER.. JOHN KARITZKY.

